Creating an imperceptible watermark which can be read by a broad range of cell phone cameras is a difficult problem.
The problems are caused by the inherently low resolution and noise levels of typical cell phone cameras. The quality
limitations of these devices compared to a typical digital camera are caused by the small size of the cell phone and cost
trade-offs made by the manufacturer.
In order to achieve this, a low resolution watermark is required which can be resolved by a typical cell phone camera.
The visibility of a traditional luminance watermark was too great at this lower resolution, so a chrominance watermark
was developed. The chrominance watermark takes advantage of the relatively low sensitivity of the human visual system
to chrominance changes. This enables a chrominance watermark to be inserted into an image which is imperceptible to
the human eye but can be read using a typical cell phone camera.
Sample images will be presented showing images with a very low visibility which can be easily read by a typical cell